Intra and interobserver variability of renal allograft ultrasound volume and resistive index measurements

PURPOSE: Aim of the present study was to evaluate the repeatability and reproducibility of the Doppler Resistive Index (R.I.) and the Ultrasound renal volume measurement in renal transplants. MATERIALS AND METHODS: Twenty-six consecutive patients (18 men, 8 women) mean age of 42,8+/-12,4 years (M+/-SD) (range 22-65 years) were studied twice by each of two trained sonographers using a color Doppler ultrasound scanner. Twelve of them had a normal allograft function (defined as stable serum creatinine levels = or <123,76 micromol/L), whilst the remaining 14 had decreased allograft function (serum creatinine 132.6-265.2 micromol/L). Results were given as mean of 6 measurements performed at upper, middle and lower pole of the kidney. Intra- and interobserver variability was assessed by the repeatability coefficient and coefficient of variation (CV). RESULTS: Regarding Resistive Index measurement, repeatability coefficient was between 0.04 and 0.06 and the coefficient of variation was <5%. The analysis of the Student's t test did not show any significant difference between the measurements (t=0.15; p=0.87 n.s.). A good reproducibility was also detected in US measurements of renal length and volume. CONCLUSIONS: These results suggest that Color Doppler Resistive Index measurements of renal allograft and Ultrasound renal volume measurements are repeatable and reproducible.